The present invention generally relates to a no-needle blood access device for hemodialysis. More specifically, the present invention relates to a no-needle blood access device for hemodialysis which has a mechanism of simple structure and does not need a caregiver.
Hemodialysis is used widely as a remedy for treating kidney insufficiency. In many cases, a surgical short circuit which is commonly referred to as xe2x80x9cshunt xe2x80x9d is implanted in a blood vessel or blood vessels of the patient suffering from serious kidney disease, because such a patient must receive hemodialysis treatment periodically over a long period of time. Shunts are divided broadly into two categories, an internal shunt and an external shunt. The internal shunt has a drawback that needle puncture is required during hemodialysis. On the other hand, the external shunt has a high rate of thrombosis and infection, and makes daily life more inconvenient.
To overcome these drawbacks of the prior shunts, as described in U.S. Pat. No. 4,496,350, a blood access device for hemodialysis given the tradename xe2x80x9cHemasitexe2x80x9d has been developed. This Hemasite blood access device has an advantage that needle puncture is not required, but due to its complicated structure, is costly and troublesome to handle.
Taking into consideration such circumstances, the applicant of the present invention has proposed a novel blood access device for hemodialysis in Japanese Patent No. 2983540 which corresponds to U.S. patent application Ser. No. 09/307,716 filed on May 10, 1999. This blood access device is very useful for the patient because it does not require needle puncture, and has a mechanism of simple structure, and can be manufactured at a relatively low cost, and is easy to handle. However, in the device, a caregiver is required during the beginning and the completion of the hemodialysis and thus, it is very desirable to have a blood access device for hemodialysis which does not need a caregiver, while maintaining the above described advantages.
It is therefore an object of the present invention to provide a blood access device for hemodialysis which does not require needle puncture, and which has a mechanism of simple structure, and which can be manufactured at a relatively low cost, and which is easy to handle, and which does not need a caregiver during hemodialysis.
The above and other objects of the present invention can be accomplished by a no-needle blood access device for hemodialysis comprising, a cylindrical external body, the external body including a peripheral wall and a bottom wall and opens to its top, the lower portion of the external body being provided with openings at locations diametrically facing with respect to each other, each of pipe members being mounted on the respective openings, each of first and second artificial conduits being fitted into the respective pipe member, each of the artificial conduits being anastomosed to a targeted artery or vein; and a columnar internal body fitted into the external body so as to be rotated in the external body, the internal body being provided with a first through-hole diametrically extending through the internal body in the horizontal direction at the location having a height on which the openings are mounted; the internal body being provided with a second through-hole extending between a first position spaced at an angular distance of xcex1 degrees (xcex1:acute angle) clockwise from the first through-hole in an outer surface of the internal body and having a height substantially equal to a height at which the opening locates, and a second position spaced at an angular distance of xcex1 degrees clockwise from the first through-hole in a top surface of the internal body, the internal body being also provided with a second through-hole extending between a third position spaced at an angular distance of xcex2 degrees (xcex2=180xc2x0 xe2x88x92xcex1) counterclockwise from the first through-hole in the outer surface of the internal body and having a height substantially equal to a height at which the opening locates, and a fourth position spaced at an angular distance of xcex2 degrees counterclockwise from the first through-hole in the top surface, whereby the device is arranged such that, when the internal body is rotated so that the first through-hole communicates with the openings, the first artificial conduit is in communication with the second artificial conduit through the first through-hole, and when the internal body is rotated so that the first position mates with one of the openings and the third position mates with the other of the openings, the second through-hole is in communication with the first artificial conduit and the third through-hole is in communication with the second artificial conduit.
In a preferred aspect of the present invention, a cannula assembly connected to a dialyzer is further provided, the cannula assembly including a disk provided with a pair of through-holes at side by side position, a first pair of cannulas connected to one end of the through-holes of the disk respectively so as to be in communication with the through-holes of the disk, and a second pair of cannulas connected to the other end of the through-holes of the disk so as to be in communication with the through-holes of the disk, whereby each of the first pair of the cannulas assembly is inserted into the second and third through-holes of the internal body, and the internal body is rotated in the external body so that the second through-holes communicates with the first artificial conduit and the third through-holes communicates with the second artificial conduit to effect hemodialysis.
In another preferred aspect of the present invention, the degree xcex1 is 90xc2x0.
In a further preferred aspect of the present invention, finger grips for rotating the internal body are provided at the top surface of the internal body.
In a further preferred aspect of the present invention, the inner height of the external body is selected to be substantially equal to the sum of the height of the internal body and the height of the disk of the cannula assembly.
The above and other objects and features of the present invention will become apparent from the following description made with reference to the accompanying drawings.